1. Field of the Invention
The present invention relates to a laser medium for use in an optical waveguide laser (hereunder sometimes referred to as a waveguide laser medium) which performs light amplification or laser oscillation by using an optical waveguide containing active material and to an optical waveguide laser (hereunder sometimes referred to simply as a waveguide laser) employing the waveguide laser medium.
2. Description of the Related Art
As examples of a conventional waveguide laser medium and a conventional waveguide laser, are known the waveguide laser medium and the waveguide laser which are previously proposed by applicants of the instant application (see Japanese Unexamined Patent Publication (Kokai Tokkyo Koho) No. 63-29986).
The previously proposed waveguide laser medium and waveguide laser are adapted to effect light amplification or optical oscillation by irradiating pump light into a waveguide which contains active ions and is formed in a substrate.
Further, the previously proposed waveguide laser medium and waveguide laser are obtained by forming a portion having a high refractive index as an optical waveguide by performing ion exchange on a part of a glass substrate made of glass (hereunder sometimes referred to as laser glass) containing active ions. Namely, alkaline ions (hereunder sometimes referred to as A-ions) contained in the laser glass are exchanged for ions of another kind (hereunder sometimes referred to as B-ions) which can increase the refractive index of the laser glass. Thereby, a portion, in which the A-ions are exchanged for the B-ions, comes to have a high refractive index and thus becomes an optical waveguide.
Further, it is necessary for obtaining a waveguide laser medium and waveguide laser having desired performance to meet the following conditions .circle.1, .circle.2 and .circle.3 :
.circle.1 The ion exchange of A-ions for B-ions can be efficiently performed in a sufficiently short time.
.circle.2 The ionic radius of an A-ion is nearly equal to that of a B-ion in such a manner to prevent occurrence of a crack in the substrate at the time of the ion exchange or of distortion of the substrate after the ion exchange.
.circle.3 The ion exchange should be effected in such a manner not to deteriorate the characteristics of the waveguide laser.
Subsequent research reveals that it is necessary for satisfying the foregoing requirements .circle.1 , .circle.2 and .circle.3 to carefully select kinds and quantities of the A-ion and the B-ion and a sort of laser glass. The present invention is accomplished to resolve such a problem.
It is therefore an object of the present invention to provide a waveguide laser medium, in which the ion exchange can be efficiently performed without the occurence of a crack and furthermore light amplification, as well as laser oscillation, can be efficiently performed, and a waveguide laser using such a waveguide laser medium.